The present invention relates to syndiotactic vinyl aromatic polymer fibers and applications thereof.
Syndiotactic vinyl aromatic polymers such as syndiotactic polystyrene (SPS) are useful polymers having a high melting point and crystallization rate as well as excellent heat and chemical resistance. However, in some applications such as in cast-tenter films and fibers, the melt strength is insufficient at processing temperatures to obtain desirable properties.
Syndiotactic copolymers have also been developed having superior heat and chemical resistance. U.S. Pat. No. 5,202,402 issued to Funaki et al. utilizes a difunctional monomer to form a syndiotactic copolymer with styrene, however, the polymer fully crosslinks at high temperatures, forming a thermoset and cannot be melt processed.
Fibers have been made previously from linear syndiotactic vinyl aromatic polymers as described in U.S. Pat. No. 5,145,631 and U.S. Pat. No. 5,021,288 issued to Jezic. However, due to melt strength limitations, these fibers are limited by their diameter and strength.
Therefore, it would be useful to obtain fibers having smaller fiber diameters, increased strength and improved processability, from a syndiotactic vinyl aromatic polymer which retains good melt strength and melt processability at high temperatures.